Suzuki TS185 Jetting Issue

| 10/22/2019 9:53:00 AM

Motorcycle Classics tech expert Keith Fellenstein
Editor’s note: If you’re having trouble with that old Suzuki, BSA or BMW, Keith Fellenstein is your guy. From motorcycle tuning tips to detailed motorcycle engine repair, he can draw from a wealth of experience to help guide you to success. Send questions to: Keith’s Garage, Motorcycle Classics, 1503 SW 42nd St., Topeka, KS 66609, or send an email with “Keith’s Garage” as the subject.

Q: A year ago I picked up a nice 1975 Suzuki TS185 and have been restoring and riding it, reminding me of my youth. I owned a 1972 and 1974 185 along with many other RM and TS models when they were new models.

My problem is the bike runs very nice, but from maybe 5/8 to full throttle it seems to blubber. My thinking was that it must have the wrong main jet, but I checked and it has the correct No. 125 jet. I did find and repair a couple small exhaust pipe cracks.

I have moved the needle clip up and down but now I am stumped. I have the carb somewhat apart and soaking in cleaner now and a new No. 125 jet has arrived in the mail. Do you have any suggestions? I am having a great time tinkering with the bike, but this is making me pull my hair out. Thanks.

—  Steve Foley/via email

A: Steve, you may have the correct numbered jet installed, but do you know if it is in original condition? Back in the day of expensive, hard-to-find parts and bad information, many a main jet was drilled out thinking that more gas means go faster. Try your replacement jet and see if that makes a difference, if not try a No. 120 or No. 115 and see if that changes things. Don’t go too lean too fast, that leads to piston seizure.

12/11/2019 6:29:21 PM

Sometimes a bad/leaky float/needle/seat can cause weird carburation at different rpm and throttle settings...

11/11/2019 1:08:26 PM

I’ve into the same problem with many 2 stroke bikes that didn’t run cleanly in the mid range. What I found was the needle jet was worn and had become oval causing the needle to meter the fuel correctly. Replacing the needle jet and jet needle with stock or as close as you can get has corrected my problem every time. Good luck!

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